All motors are tested at Retrotec facilities for 1.5 hours under full current and stress. The motors which shut off due to excess heat are rejected, and sent back to the beginning of the production line. Some users, however, may still encounter problems in the field. Below are some points that may be followed to remedy a specific problem.
· Make sure the motor runs as close to full speed as possible. The faster it runs, the more air goes through the motor. A rule of thumb is to have the Fan Pressure over 100 Pa and the motor running near full speed. The motor heats up the most at ¾-speed where it draws 13 amps at 120 volts. At full speed the motor will draw less current!
· Make sure the C8 Range Plate has the cooling ports in line with the ones on the motor cover. If the mounting indicator sign is in the correct position, this will ensure the ports are fully open.
· Ensure that the switch on the speed controller is in the off (0) position at the rocker switch, not just turned down. If left on low speed with the blade not turning, the controller and the motor will be stressed.
· The thermal breakers that shut down the motor are not adjustable. To learn when maximum heat is created, put a current meter on the fan, and adjust the fan speed to see when it is pulling maximum current, and therefore creating maximum heat.
· More current = more heat.
· More airflow through motor = less heat.
A more drastic solution is to change the blade or to cut a quarter inch off the blade tips and re-balance the blade to reduce the load on the motor.